Weatherstripping material is important in the conservation of energy and is used to provide a barrier to air between a variety of fixed and movable elements, such as between slidable or swingable elements including windows or doors and the like, and the fixed elements within which they are mounted for movement. The best type of weatherstripping barrier is a solid element, such as a plastomeric or elastomeric fin or the like, which presents a solid barrier to prevent the passage of cold air from one side of the weatherstripping, or warm air from the other side. Such weatherstripping material has been known and used for many years. A more recent development is the so-called pile-type of weatherstripping, the major advantage of which is its high customer acceptance; in essence, pile-type weatherstripping has achieved its great success because the ultimate customer, i.e. the consumer, likes the way it looks.
However, one of the problems with pile-type weatherstripping was that the pile fibers permitted the passage therethrough of air, and therefore this type of weatherstripping in some environments failed to provide a solution for the very problem for which it was needed, namely to provide an air barrier. This problem was essentially solved by the 1965 Horton U.S. Pat. No. 3,175,256, which provided an impervious barrier fin within the pile. The product of Horton thus combined the air impervious fin with the attractive pile material.
When using a pile-type of weatherstripping such as shown in the Horton patent, the surface against which the top end of the weatherstripping should seal, should be spaced from the surface in which the weatherstripping is mounted by a distance equal to the height of the weatherstripping. In actual practice, however, installers of windows and doors are seldom sufficiently careful to provide this spacing; and the tendancy, in order to avoid a gap between the top of the weatherstripping and the opposite surface against which it is to seal, is to make the distance less than the height of the weatherstripping, thereby causing a compression of the weatherstripping during use. When the weatherstripping is so compressed, there is often created a substantial frictional drag which may be considerable from the point of view of the consumer, because substantial breakaway force may be required to move the movable element (e.g. a sliding window) from the fixed element (e.g. the window frame). This may be an especially difficult problem for children, the elderly, handicapped or other persons with little strength.
One partial solution to this problem which has been in common use for many years is to extend the height of the film in the Horton weatherstripping above the height of the pile. This expedient permits the installer a somewhat larger margin of error, because the sliding or moving surface (e.g. the contacting surface of the window or door) can be located anywhere between the top of the pile and the top of the fin. This expedient is not entirely satisfactory, however, because the appearance is sometimes less than satisfactory and if the installer continues to compress the pile, the problem of excessive breakaway force continues to exist.
The U.S. Patent to Yackiw No. 4,242,392 is of interest in showing a pile-type, fin weatherstripping material wherein the upwardly projecting, fin is formed of a porous material impregnated with paraffin, the paraffin being stated to act as a lubricant for the sliding surface against which the weatherstripping material seals. However, insofar as is known, this product has apparently not been satisfactory and has never entered the marketplace. In use, the paraffin lubricant would soon rub off the exposed tip of the fin and there is no means provided for supplying lubricant over an extended period of time.
Another patent of interest is the Johnson et al U.S. Pat. No. 3,745,053. This patent describes an embodiment in FIG. 6 where a space is provided beneath the barrier fin, and the space is filled with a non-adhesive gasket material such as grease, wax or silicone grease, in order to seal such space between the barrier fin and the base. It is evident that such non-adhesive gasket material, even if it is a grease, is not a lubricating grease and is not of a character, and not placed in a proper position, so that it may migrate from its desired location between the barrier fin and the base to a location where it might act as a lubricant.
The need continues to exist for a pile-type, fin weatherstrip which is more tolerant of improper installation, i.e. one that can be placed under substantial compression due to faulty installation, yet will not result in the creation of so much friction that the breakaway force required to open a sliding door or window becomes a problem to any member of the consuming public.